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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Copyright (C) 2009 The Guava Authors<a name="line.2"></a>
<span class="sourceLineNo">003</span> *<a name="line.3"></a>
<span class="sourceLineNo">004</span> * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except<a name="line.4"></a>
<span class="sourceLineNo">005</span> * in compliance with the License. You may obtain a copy of the License at<a name="line.5"></a>
<span class="sourceLineNo">006</span> *<a name="line.6"></a>
<span class="sourceLineNo">007</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.7"></a>
<span class="sourceLineNo">008</span> *<a name="line.8"></a>
<span class="sourceLineNo">009</span> * Unless required by applicable law or agreed to in writing, software distributed under the License<a name="line.9"></a>
<span class="sourceLineNo">010</span> * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express<a name="line.10"></a>
<span class="sourceLineNo">011</span> * or implied. See the License for the specific language governing permissions and limitations under<a name="line.11"></a>
<span class="sourceLineNo">012</span> * the License.<a name="line.12"></a>
<span class="sourceLineNo">013</span> */<a name="line.13"></a>
<span class="sourceLineNo">014</span><a name="line.14"></a>
<span class="sourceLineNo">015</span>package com.google.common.collect;<a name="line.15"></a>
<span class="sourceLineNo">016</span><a name="line.16"></a>
<span class="sourceLineNo">017</span>import static com.google.common.base.Objects.firstNonNull;<a name="line.17"></a>
<span class="sourceLineNo">018</span>import static com.google.common.base.Preconditions.checkArgument;<a name="line.18"></a>
<span class="sourceLineNo">019</span>import static com.google.common.base.Preconditions.checkNotNull;<a name="line.19"></a>
<span class="sourceLineNo">020</span>import static com.google.common.base.Preconditions.checkState;<a name="line.20"></a>
<span class="sourceLineNo">021</span><a name="line.21"></a>
<span class="sourceLineNo">022</span>import com.google.common.annotations.GwtCompatible;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import com.google.common.annotations.GwtIncompatible;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import com.google.common.base.Ascii;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import com.google.common.base.Equivalence;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import com.google.common.base.Function;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import com.google.common.base.Objects;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import com.google.common.base.Throwables;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import com.google.common.base.Ticker;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import com.google.common.collect.MapMakerInternalMap.Strength;<a name="line.30"></a>
<span class="sourceLineNo">031</span><a name="line.31"></a>
<span class="sourceLineNo">032</span>import java.io.Serializable;<a name="line.32"></a>
<span class="sourceLineNo">033</span>import java.lang.ref.SoftReference;<a name="line.33"></a>
<span class="sourceLineNo">034</span>import java.lang.ref.WeakReference;<a name="line.34"></a>
<span class="sourceLineNo">035</span>import java.util.AbstractMap;<a name="line.35"></a>
<span class="sourceLineNo">036</span>import java.util.Collections;<a name="line.36"></a>
<span class="sourceLineNo">037</span>import java.util.ConcurrentModificationException;<a name="line.37"></a>
<span class="sourceLineNo">038</span>import java.util.Map;<a name="line.38"></a>
<span class="sourceLineNo">039</span>import java.util.Set;<a name="line.39"></a>
<span class="sourceLineNo">040</span>import java.util.concurrent.ConcurrentHashMap;<a name="line.40"></a>
<span class="sourceLineNo">041</span>import java.util.concurrent.ConcurrentMap;<a name="line.41"></a>
<span class="sourceLineNo">042</span>import java.util.concurrent.ExecutionException;<a name="line.42"></a>
<span class="sourceLineNo">043</span>import java.util.concurrent.TimeUnit;<a name="line.43"></a>
<span class="sourceLineNo">044</span><a name="line.44"></a>
<span class="sourceLineNo">045</span>import javax.annotation.Nullable;<a name="line.45"></a>
<span class="sourceLineNo">046</span><a name="line.46"></a>
<span class="sourceLineNo">047</span>/**<a name="line.47"></a>
<span class="sourceLineNo">048</span> * &lt;p&gt;A builder of {@link ConcurrentMap} instances having any combination of the following features:<a name="line.48"></a>
<span class="sourceLineNo">049</span> *<a name="line.49"></a>
<span class="sourceLineNo">050</span> * &lt;ul&gt;<a name="line.50"></a>
<span class="sourceLineNo">051</span> * &lt;li&gt;keys or values automatically wrapped in {@linkplain WeakReference weak} or {@linkplain<a name="line.51"></a>
<span class="sourceLineNo">052</span> *     SoftReference soft} references<a name="line.52"></a>
<span class="sourceLineNo">053</span> * &lt;li&gt;notification of evicted (or otherwise removed) entries<a name="line.53"></a>
<span class="sourceLineNo">054</span> * &lt;li&gt;on-demand computation of values for keys not already present<a name="line.54"></a>
<span class="sourceLineNo">055</span> * &lt;/ul&gt;<a name="line.55"></a>
<span class="sourceLineNo">056</span> *<a name="line.56"></a>
<span class="sourceLineNo">057</span> * &lt;p&gt;Usage example: &lt;pre&gt;   {@code<a name="line.57"></a>
<span class="sourceLineNo">058</span> *<a name="line.58"></a>
<span class="sourceLineNo">059</span> *   ConcurrentMap&lt;Key, Graph&gt; graphs = new MapMaker()<a name="line.59"></a>
<span class="sourceLineNo">060</span> *       .concurrencyLevel(4)<a name="line.60"></a>
<span class="sourceLineNo">061</span> *       .weakKeys()<a name="line.61"></a>
<span class="sourceLineNo">062</span> *       .makeComputingMap(<a name="line.62"></a>
<span class="sourceLineNo">063</span> *           new Function&lt;Key, Graph&gt;() {<a name="line.63"></a>
<span class="sourceLineNo">064</span> *             public Graph apply(Key key) {<a name="line.64"></a>
<span class="sourceLineNo">065</span> *               return createExpensiveGraph(key);<a name="line.65"></a>
<span class="sourceLineNo">066</span> *             }<a name="line.66"></a>
<span class="sourceLineNo">067</span> *           });}&lt;/pre&gt;<a name="line.67"></a>
<span class="sourceLineNo">068</span> *<a name="line.68"></a>
<span class="sourceLineNo">069</span> * These features are all optional; {@code new MapMaker().makeMap()} returns a valid concurrent map<a name="line.69"></a>
<span class="sourceLineNo">070</span> * that behaves similarly to a {@link ConcurrentHashMap}.<a name="line.70"></a>
<span class="sourceLineNo">071</span> *<a name="line.71"></a>
<span class="sourceLineNo">072</span> * &lt;p&gt;The returned map is implemented as a hash table with similar performance characteristics to<a name="line.72"></a>
<span class="sourceLineNo">073</span> * {@link ConcurrentHashMap}. It supports all optional operations of the {@code ConcurrentMap}<a name="line.73"></a>
<span class="sourceLineNo">074</span> * interface. It does not permit null keys or values.<a name="line.74"></a>
<span class="sourceLineNo">075</span> *<a name="line.75"></a>
<span class="sourceLineNo">076</span> * &lt;p&gt;&lt;b&gt;Note:&lt;/b&gt; by default, the returned map uses equality comparisons (the {@link Object#equals<a name="line.76"></a>
<span class="sourceLineNo">077</span> * equals} method) to determine equality for keys or values. However, if {@link #weakKeys} or {@link<a name="line.77"></a>
<span class="sourceLineNo">078</span> * #softKeys} was specified, the map uses identity ({@code ==}) comparisons instead for keys.<a name="line.78"></a>
<span class="sourceLineNo">079</span> * Likewise, if {@link #weakValues} or {@link #softValues} was specified, the map uses identity<a name="line.79"></a>
<span class="sourceLineNo">080</span> * comparisons for values.<a name="line.80"></a>
<span class="sourceLineNo">081</span> *<a name="line.81"></a>
<span class="sourceLineNo">082</span> * &lt;p&gt;The view collections of the returned map have &lt;i&gt;weakly consistent iterators&lt;/i&gt;. This means<a name="line.82"></a>
<span class="sourceLineNo">083</span> * that they are safe for concurrent use, but if other threads modify the map after the iterator is<a name="line.83"></a>
<span class="sourceLineNo">084</span> * created, it is undefined which of these changes, if any, are reflected in that iterator. These<a name="line.84"></a>
<span class="sourceLineNo">085</span> * iterators never throw {@link ConcurrentModificationException}.<a name="line.85"></a>
<span class="sourceLineNo">086</span> *<a name="line.86"></a>
<span class="sourceLineNo">087</span> * &lt;p&gt;If soft or weak references were requested, it is possible for a key or value present in the<a name="line.87"></a>
<span class="sourceLineNo">088</span> * the map to be reclaimed by the garbage collector. If this happens, the entry automatically<a name="line.88"></a>
<span class="sourceLineNo">089</span> * disappears from the map. A partially-reclaimed entry is never exposed to the user. Any {@link<a name="line.89"></a>
<span class="sourceLineNo">090</span> * java.util.Map.Entry} instance retrieved from the map's {@linkplain Map#entrySet entry set} is a<a name="line.90"></a>
<span class="sourceLineNo">091</span> * snapshot of that entry's state at the time of retrieval; such entries do, however, support {@link<a name="line.91"></a>
<span class="sourceLineNo">092</span> * java.util.Map.Entry#setValue}, which simply calls {@link Map#put} on the entry's key.<a name="line.92"></a>
<span class="sourceLineNo">093</span> *<a name="line.93"></a>
<span class="sourceLineNo">094</span> * &lt;p&gt;The maps produced by {@code MapMaker} are serializable, and the deserialized maps retain all<a name="line.94"></a>
<span class="sourceLineNo">095</span> * the configuration properties of the original map. During deserialization, if the original map had<a name="line.95"></a>
<span class="sourceLineNo">096</span> * used soft or weak references, the entries are reconstructed as they were, but it's not unlikely<a name="line.96"></a>
<span class="sourceLineNo">097</span> * they'll be quickly garbage-collected before they are ever accessed.<a name="line.97"></a>
<span class="sourceLineNo">098</span> *<a name="line.98"></a>
<span class="sourceLineNo">099</span> * &lt;p&gt;{@code new MapMaker().weakKeys().makeMap()} is a recommended replacement for {@link<a name="line.99"></a>
<span class="sourceLineNo">100</span> * java.util.WeakHashMap}, but note that it compares keys using object identity whereas {@code<a name="line.100"></a>
<span class="sourceLineNo">101</span> * WeakHashMap} uses {@link Object#equals}.<a name="line.101"></a>
<span class="sourceLineNo">102</span> *<a name="line.102"></a>
<span class="sourceLineNo">103</span> * @author Bob Lee<a name="line.103"></a>
<span class="sourceLineNo">104</span> * @author Charles Fry<a name="line.104"></a>
<span class="sourceLineNo">105</span> * @author Kevin Bourrillion<a name="line.105"></a>
<span class="sourceLineNo">106</span> * @since 2.0 (imported from Google Collections Library)<a name="line.106"></a>
<span class="sourceLineNo">107</span> */<a name="line.107"></a>
<span class="sourceLineNo">108</span>@GwtCompatible(emulated = true)<a name="line.108"></a>
<span class="sourceLineNo">109</span>public final class MapMaker extends GenericMapMaker&lt;Object, Object&gt; {<a name="line.109"></a>
<span class="sourceLineNo">110</span>  private static final int DEFAULT_INITIAL_CAPACITY = 16;<a name="line.110"></a>
<span class="sourceLineNo">111</span>  private static final int DEFAULT_CONCURRENCY_LEVEL = 4;<a name="line.111"></a>
<span class="sourceLineNo">112</span>  private static final int DEFAULT_EXPIRATION_NANOS = 0;<a name="line.112"></a>
<span class="sourceLineNo">113</span><a name="line.113"></a>
<span class="sourceLineNo">114</span>  static final int UNSET_INT = -1;<a name="line.114"></a>
<span class="sourceLineNo">115</span><a name="line.115"></a>
<span class="sourceLineNo">116</span>  // TODO(kevinb): dispense with this after benchmarking<a name="line.116"></a>
<span class="sourceLineNo">117</span>  boolean useCustomMap;<a name="line.117"></a>
<span class="sourceLineNo">118</span><a name="line.118"></a>
<span class="sourceLineNo">119</span>  int initialCapacity = UNSET_INT;<a name="line.119"></a>
<span class="sourceLineNo">120</span>  int concurrencyLevel = UNSET_INT;<a name="line.120"></a>
<span class="sourceLineNo">121</span>  int maximumSize = UNSET_INT;<a name="line.121"></a>
<span class="sourceLineNo">122</span><a name="line.122"></a>
<span class="sourceLineNo">123</span>  Strength keyStrength;<a name="line.123"></a>
<span class="sourceLineNo">124</span>  Strength valueStrength;<a name="line.124"></a>
<span class="sourceLineNo">125</span><a name="line.125"></a>
<span class="sourceLineNo">126</span>  long expireAfterWriteNanos = UNSET_INT;<a name="line.126"></a>
<span class="sourceLineNo">127</span>  long expireAfterAccessNanos = UNSET_INT;<a name="line.127"></a>
<span class="sourceLineNo">128</span><a name="line.128"></a>
<span class="sourceLineNo">129</span>  RemovalCause nullRemovalCause;<a name="line.129"></a>
<span class="sourceLineNo">130</span><a name="line.130"></a>
<span class="sourceLineNo">131</span>  Equivalence&lt;Object&gt; keyEquivalence;<a name="line.131"></a>
<span class="sourceLineNo">132</span><a name="line.132"></a>
<span class="sourceLineNo">133</span>  Ticker ticker;<a name="line.133"></a>
<span class="sourceLineNo">134</span><a name="line.134"></a>
<span class="sourceLineNo">135</span>  /**<a name="line.135"></a>
<span class="sourceLineNo">136</span>   * Constructs a new {@code MapMaker} instance with default settings, including strong keys, strong<a name="line.136"></a>
<span class="sourceLineNo">137</span>   * values, and no automatic eviction of any kind.<a name="line.137"></a>
<span class="sourceLineNo">138</span>   */<a name="line.138"></a>
<span class="sourceLineNo">139</span>  public MapMaker() {}<a name="line.139"></a>
<span class="sourceLineNo">140</span><a name="line.140"></a>
<span class="sourceLineNo">141</span>  /**<a name="line.141"></a>
<span class="sourceLineNo">142</span>   * Sets a custom {@code Equivalence} strategy for comparing keys.<a name="line.142"></a>
<span class="sourceLineNo">143</span>   *<a name="line.143"></a>
<span class="sourceLineNo">144</span>   * &lt;p&gt;By default, the map uses {@link Equivalence#identity} to determine key equality when<a name="line.144"></a>
<span class="sourceLineNo">145</span>   * {@link #weakKeys} or {@link #softKeys} is specified, and {@link Equivalence#equals()}<a name="line.145"></a>
<span class="sourceLineNo">146</span>   * otherwise. The only place this is used is in {@link Interners.WeakInterner}.<a name="line.146"></a>
<span class="sourceLineNo">147</span>   */<a name="line.147"></a>
<span class="sourceLineNo">148</span>  @GwtIncompatible("To be supported")<a name="line.148"></a>
<span class="sourceLineNo">149</span>  @Override<a name="line.149"></a>
<span class="sourceLineNo">150</span>  MapMaker keyEquivalence(Equivalence&lt;Object&gt; equivalence) {<a name="line.150"></a>
<span class="sourceLineNo">151</span>    checkState(keyEquivalence == null, "key equivalence was already set to %s", keyEquivalence);<a name="line.151"></a>
<span class="sourceLineNo">152</span>    keyEquivalence = checkNotNull(equivalence);<a name="line.152"></a>
<span class="sourceLineNo">153</span>    this.useCustomMap = true;<a name="line.153"></a>
<span class="sourceLineNo">154</span>    return this;<a name="line.154"></a>
<span class="sourceLineNo">155</span>  }<a name="line.155"></a>
<span class="sourceLineNo">156</span><a name="line.156"></a>
<span class="sourceLineNo">157</span>  Equivalence&lt;Object&gt; getKeyEquivalence() {<a name="line.157"></a>
<span class="sourceLineNo">158</span>    return firstNonNull(keyEquivalence, getKeyStrength().defaultEquivalence());<a name="line.158"></a>
<span class="sourceLineNo">159</span>  }<a name="line.159"></a>
<span class="sourceLineNo">160</span><a name="line.160"></a>
<span class="sourceLineNo">161</span>  /**<a name="line.161"></a>
<span class="sourceLineNo">162</span>   * Sets the minimum total size for the internal hash tables. For example, if the initial capacity<a name="line.162"></a>
<span class="sourceLineNo">163</span>   * is {@code 60}, and the concurrency level is {@code 8}, then eight segments are created, each<a name="line.163"></a>
<span class="sourceLineNo">164</span>   * having a hash table of size eight. Providing a large enough estimate at construction time<a name="line.164"></a>
<span class="sourceLineNo">165</span>   * avoids the need for expensive resizing operations later, but setting this value unnecessarily<a name="line.165"></a>
<span class="sourceLineNo">166</span>   * high wastes memory.<a name="line.166"></a>
<span class="sourceLineNo">167</span>   *<a name="line.167"></a>
<span class="sourceLineNo">168</span>   * @throws IllegalArgumentException if {@code initialCapacity} is negative<a name="line.168"></a>
<span class="sourceLineNo">169</span>   * @throws IllegalStateException if an initial capacity was already set<a name="line.169"></a>
<span class="sourceLineNo">170</span>   */<a name="line.170"></a>
<span class="sourceLineNo">171</span>  @Override<a name="line.171"></a>
<span class="sourceLineNo">172</span>  public MapMaker initialCapacity(int initialCapacity) {<a name="line.172"></a>
<span class="sourceLineNo">173</span>    checkState(this.initialCapacity == UNSET_INT, "initial capacity was already set to %s",<a name="line.173"></a>
<span class="sourceLineNo">174</span>        this.initialCapacity);<a name="line.174"></a>
<span class="sourceLineNo">175</span>    checkArgument(initialCapacity &gt;= 0);<a name="line.175"></a>
<span class="sourceLineNo">176</span>    this.initialCapacity = initialCapacity;<a name="line.176"></a>
<span class="sourceLineNo">177</span>    return this;<a name="line.177"></a>
<span class="sourceLineNo">178</span>  }<a name="line.178"></a>
<span class="sourceLineNo">179</span><a name="line.179"></a>
<span class="sourceLineNo">180</span>  int getInitialCapacity() {<a name="line.180"></a>
<span class="sourceLineNo">181</span>    return (initialCapacity == UNSET_INT) ? DEFAULT_INITIAL_CAPACITY : initialCapacity;<a name="line.181"></a>
<span class="sourceLineNo">182</span>  }<a name="line.182"></a>
<span class="sourceLineNo">183</span><a name="line.183"></a>
<span class="sourceLineNo">184</span>  /**<a name="line.184"></a>
<span class="sourceLineNo">185</span>   * Specifies the maximum number of entries the map may contain. Note that the map &lt;b&gt;may evict an<a name="line.185"></a>
<span class="sourceLineNo">186</span>   * entry before this limit is exceeded&lt;/b&gt;. As the map size grows close to the maximum, the map<a name="line.186"></a>
<span class="sourceLineNo">187</span>   * evicts entries that are less likely to be used again. For example, the map may evict an entry<a name="line.187"></a>
<span class="sourceLineNo">188</span>   * because it hasn't been used recently or very often.<a name="line.188"></a>
<span class="sourceLineNo">189</span>   *<a name="line.189"></a>
<span class="sourceLineNo">190</span>   * &lt;p&gt;When {@code size} is zero, elements can be successfully added to the map, but are evicted<a name="line.190"></a>
<span class="sourceLineNo">191</span>   * immediately. This has the same effect as invoking {@link #expireAfterWrite<a name="line.191"></a>
<span class="sourceLineNo">192</span>   * expireAfterWrite}{@code (0, unit)} or {@link #expireAfterAccess expireAfterAccess}{@code (0,<a name="line.192"></a>
<span class="sourceLineNo">193</span>   * unit)}. It can be useful in testing, or to disable caching temporarily without a code change.<a name="line.193"></a>
<span class="sourceLineNo">194</span>   *<a name="line.194"></a>
<span class="sourceLineNo">195</span>   * &lt;p&gt;Caching functionality in {@code MapMaker} is being moved to<a name="line.195"></a>
<span class="sourceLineNo">196</span>   * {@link com.google.common.cache.CacheBuilder}.<a name="line.196"></a>
<span class="sourceLineNo">197</span>   *<a name="line.197"></a>
<span class="sourceLineNo">198</span>   * @param size the maximum size of the map<a name="line.198"></a>
<span class="sourceLineNo">199</span>   * @throws IllegalArgumentException if {@code size} is negative<a name="line.199"></a>
<span class="sourceLineNo">200</span>   * @throws IllegalStateException if a maximum size was already set<a name="line.200"></a>
<span class="sourceLineNo">201</span>   * @deprecated Caching functionality in {@code MapMaker} is being moved to<a name="line.201"></a>
<span class="sourceLineNo">202</span>   *     {@link com.google.common.cache.CacheBuilder}, with {@link #maximumSize} being<a name="line.202"></a>
<span class="sourceLineNo">203</span>   *     replaced by {@link com.google.common.cache.CacheBuilder#maximumSize}. Note that {@code<a name="line.203"></a>
<span class="sourceLineNo">204</span>   *     CacheBuilder} is simply an enhanced API for an implementation which was branched from<a name="line.204"></a>
<span class="sourceLineNo">205</span>   *     {@code MapMaker}.<a name="line.205"></a>
<span class="sourceLineNo">206</span>   */<a name="line.206"></a>
<span class="sourceLineNo">207</span>  @Deprecated<a name="line.207"></a>
<span class="sourceLineNo">208</span>  @Override<a name="line.208"></a>
<span class="sourceLineNo">209</span>  MapMaker maximumSize(int size) {<a name="line.209"></a>
<span class="sourceLineNo">210</span>    checkState(this.maximumSize == UNSET_INT, "maximum size was already set to %s",<a name="line.210"></a>
<span class="sourceLineNo">211</span>        this.maximumSize);<a name="line.211"></a>
<span class="sourceLineNo">212</span>    checkArgument(size &gt;= 0, "maximum size must not be negative");<a name="line.212"></a>
<span class="sourceLineNo">213</span>    this.maximumSize = size;<a name="line.213"></a>
<span class="sourceLineNo">214</span>    this.useCustomMap = true;<a name="line.214"></a>
<span class="sourceLineNo">215</span>    if (maximumSize == 0) {<a name="line.215"></a>
<span class="sourceLineNo">216</span>      // SIZE trumps EXPIRED<a name="line.216"></a>
<span class="sourceLineNo">217</span>      this.nullRemovalCause = RemovalCause.SIZE;<a name="line.217"></a>
<span class="sourceLineNo">218</span>    }<a name="line.218"></a>
<span class="sourceLineNo">219</span>    return this;<a name="line.219"></a>
<span class="sourceLineNo">220</span>  }<a name="line.220"></a>
<span class="sourceLineNo">221</span><a name="line.221"></a>
<span class="sourceLineNo">222</span>  /**<a name="line.222"></a>
<span class="sourceLineNo">223</span>   * Guides the allowed concurrency among update operations. Used as a hint for internal sizing. The<a name="line.223"></a>
<span class="sourceLineNo">224</span>   * table is internally partitioned to try to permit the indicated number of concurrent updates<a name="line.224"></a>
<span class="sourceLineNo">225</span>   * without contention. Because assignment of entries to these partitions is not necessarily<a name="line.225"></a>
<span class="sourceLineNo">226</span>   * uniform, the actual concurrency observed may vary. Ideally, you should choose a value to<a name="line.226"></a>
<span class="sourceLineNo">227</span>   * accommodate as many threads as will ever concurrently modify the table. Using a significantly<a name="line.227"></a>
<span class="sourceLineNo">228</span>   * higher value than you need can waste space and time, and a significantly lower value can lead<a name="line.228"></a>
<span class="sourceLineNo">229</span>   * to thread contention. But overestimates and underestimates within an order of magnitude do not<a name="line.229"></a>
<span class="sourceLineNo">230</span>   * usually have much noticeable impact. A value of one permits only one thread to modify the map<a name="line.230"></a>
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<span class="sourceLineNo">258</span>   * &lt;p&gt;&lt;b&gt;Warning:&lt;/b&gt; when this method is used, the resulting map will use identity ({@code ==})<a name="line.258"></a>
<span class="sourceLineNo">259</span>   * comparison to determine equality of keys, which is a technical violation of the {@link Map}<a name="line.259"></a>
<span class="sourceLineNo">260</span>   * specification, and may not be what you expect.<a name="line.260"></a>
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<span class="sourceLineNo">280</span>   *<a name="line.280"></a>
<span class="sourceLineNo">281</span>   * &lt;p&gt;&lt;b&gt;Warning:&lt;/b&gt; when this method is used, the resulting map will use identity ({@code ==})<a name="line.281"></a>
<span class="sourceLineNo">282</span>   * comparison to determine equality of keys, which is a technical violation of the {@link Map}<a name="line.282"></a>
<span class="sourceLineNo">283</span>   * specification, and may not be what you expect.<a name="line.283"></a>
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<span class="sourceLineNo">313</span>   * Specifies that each value (not key) stored in the map should be wrapped in a<a name="line.313"></a>
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<span class="sourceLineNo">318</span>   *<a name="line.318"></a>
<span class="sourceLineNo">319</span>   * &lt;p&gt;&lt;b&gt;Warning:&lt;/b&gt; when this method is used, the resulting map will use identity ({@code ==})<a name="line.319"></a>
<span class="sourceLineNo">320</span>   * comparison to determine equality of values. This technically violates the specifications of<a name="line.320"></a>
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<span class="sourceLineNo">325</span>   *<a name="line.325"></a>
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<span class="sourceLineNo">340</span>   *<a name="line.340"></a>
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<span class="sourceLineNo">345</span>   * &lt;p&gt;&lt;b&gt;Warning:&lt;/b&gt; when this method is used, the resulting map will use identity ({@code ==})<a name="line.345"></a>
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<span class="sourceLineNo">348</span>   * {@link ConcurrentMap#remove(Object, Object) remove(Object, Object)} and<a name="line.348"></a>
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<span class="sourceLineNo">386</span>   * occasional read operations in the absense of writes; though this behavior may change in the<a name="line.386"></a>
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<span class="sourceLineNo">475</span>   * each time an entry is removed from the map by any means.<a name="line.475"></a>
<span class="sourceLineNo">476</span>   *<a name="line.476"></a>
<span class="sourceLineNo">477</span>   * &lt;p&gt;Each map built by this map maker after this method is called invokes the supplied listener<a name="line.477"></a>
<span class="sourceLineNo">478</span>   * after removing an element for any reason (see removal causes in {@link RemovalCause}). It will<a name="line.478"></a>
<span class="sourceLineNo">479</span>   * invoke the listener during invocations of any of that map's public methods (even read-only<a name="line.479"></a>
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<span class="sourceLineNo">481</span>   *<a name="line.481"></a>
<span class="sourceLineNo">482</span>   * &lt;p&gt;&lt;b&gt;Important note:&lt;/b&gt; Instead of returning &lt;i&gt;this&lt;/i&gt; as a {@code MapMaker} instance,<a name="line.482"></a>
<span class="sourceLineNo">483</span>   * this method returns {@code GenericMapMaker&lt;K, V&gt;}. From this point on, either the original<a name="line.483"></a>
<span class="sourceLineNo">484</span>   * reference or the returned reference may be used to complete configuration and build the map,<a name="line.484"></a>
<span class="sourceLineNo">485</span>   * but only the "generic" one is type-safe. That is, it will properly prevent you from building<a name="line.485"></a>
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<span class="sourceLineNo">487</span>   * provided; the {@code MapMaker} type cannot do this. For best results, simply use the standard<a name="line.487"></a>
<span class="sourceLineNo">488</span>   * method-chaining idiom, as illustrated in the documentation at top, configuring a {@code<a name="line.488"></a>
<span class="sourceLineNo">489</span>   * MapMaker} and building your {@link Map} all in a single statement.<a name="line.489"></a>
<span class="sourceLineNo">490</span>   *<a name="line.490"></a>
<span class="sourceLineNo">491</span>   * &lt;p&gt;&lt;b&gt;Warning:&lt;/b&gt; if you ignore the above advice, and use this {@code MapMaker} to build a map<a name="line.491"></a>
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<span class="sourceLineNo">495</span>   * @throws IllegalStateException if a removal listener was already set<a name="line.495"></a>
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<span class="sourceLineNo">497</span>   *     {@link com.google.common.cache.CacheBuilder}, with {@link #removalListener} being<a name="line.497"></a>
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<span class="sourceLineNo">500</span>   *     {@code MapMaker}.<a name="line.500"></a>
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<span class="sourceLineNo">519</span>   *<a name="line.519"></a>
<span class="sourceLineNo">520</span>   * &lt;p&gt;The bulk operations {@code putAll}, {@code equals}, and {@code clear} are not guaranteed to<a name="line.520"></a>
<span class="sourceLineNo">521</span>   * be performed atomically on the returned map. Additionally, {@code size} and {@code<a name="line.521"></a>
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<span class="sourceLineNo">523</span>   * writes.<a name="line.523"></a>
<span class="sourceLineNo">524</span>   *<a name="line.524"></a>
<span class="sourceLineNo">525</span>   * @return a serializable concurrent map having the requested features<a name="line.525"></a>
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<span class="sourceLineNo">538</span>   * Returns a MapMakerInternalMap for the benefit of internal callers that use features of<a name="line.538"></a>
<span class="sourceLineNo">539</span>   * that class not exposed through ConcurrentMap.<a name="line.539"></a>
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<span class="sourceLineNo">542</span>  @GwtIncompatible("MapMakerInternalMap")<a name="line.542"></a>
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<span class="sourceLineNo">549</span>   * returns an already-computed value for the given key, atomically computes it using the supplied<a name="line.549"></a>
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<span class="sourceLineNo">552</span>   * concurrently by multiple threads, but only for distinct keys.<a name="line.552"></a>
<span class="sourceLineNo">553</span>   *<a name="line.553"></a>
<span class="sourceLineNo">554</span>   * &lt;p&gt;New code should use {@link com.google.common.cache.CacheBuilder}, which supports<a name="line.554"></a>
<span class="sourceLineNo">555</span>   * {@linkplain com.google.common.cache.CacheStats statistics} collection, introduces the<a name="line.555"></a>
<span class="sourceLineNo">556</span>   * {@link com.google.common.cache.CacheLoader} interface for loading entries into the cache<a name="line.556"></a>
<span class="sourceLineNo">557</span>   * (allowing checked exceptions to be thrown in the process), and more cleanly separates<a name="line.557"></a>
<span class="sourceLineNo">558</span>   * computation from the cache's {@code Map} view.<a name="line.558"></a>
<span class="sourceLineNo">559</span>   *<a name="line.559"></a>
<span class="sourceLineNo">560</span>   * &lt;p&gt;If an entry's value has not finished computing yet, query methods besides {@code get} return<a name="line.560"></a>
<span class="sourceLineNo">561</span>   * immediately as if an entry doesn't exist. In other words, an entry isn't externally visible<a name="line.561"></a>
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<span class="sourceLineNo">563</span>   *<a name="line.563"></a>
<span class="sourceLineNo">564</span>   * &lt;p&gt;{@link Map#get} on the returned map will never return {@code null}. It may throw:<a name="line.564"></a>
<span class="sourceLineNo">565</span>   *<a name="line.565"></a>
<span class="sourceLineNo">566</span>   * &lt;ul&gt;<a name="line.566"></a>
<span class="sourceLineNo">567</span>   * &lt;li&gt;{@link NullPointerException} if the key is null or the computing function returns a null<a name="line.567"></a>
<span class="sourceLineNo">568</span>   *     result<a name="line.568"></a>
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<span class="sourceLineNo">570</span>   * exception is already of type {@link ComputationException} it is propagated directly; otherwise<a name="line.570"></a>
<span class="sourceLineNo">571</span>   * it is wrapped.<a name="line.571"></a>
<span class="sourceLineNo">572</span>   * &lt;/ul&gt;<a name="line.572"></a>
<span class="sourceLineNo">573</span>   *<a name="line.573"></a>
<span class="sourceLineNo">574</span>   * &lt;p&gt;&lt;b&gt;Note:&lt;/b&gt; Callers of {@code get} &lt;i&gt;must&lt;/i&gt; ensure that the key argument is of type<a name="line.574"></a>
<span class="sourceLineNo">575</span>   * {@code K}. The {@code get} method accepts {@code Object}, so the key type is not checked at<a name="line.575"></a>
<span class="sourceLineNo">576</span>   * compile time. Passing an object of a type other than {@code K} can result in that object being<a name="line.576"></a>
<span class="sourceLineNo">577</span>   * unsafely passed to the computing function as type {@code K}, and unsafely stored in the map.<a name="line.577"></a>
<span class="sourceLineNo">578</span>   *<a name="line.578"></a>
<span class="sourceLineNo">579</span>   * &lt;p&gt;If {@link Map#put} is called before a computation completes, other threads waiting on the<a name="line.579"></a>
<span class="sourceLineNo">580</span>   * computation will wake up and return the stored value.<a name="line.580"></a>
<span class="sourceLineNo">581</span>   *<a name="line.581"></a>
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<span class="sourceLineNo">584</span>   *<a name="line.584"></a>
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<span class="sourceLineNo">586</span>   * concurrently by multiple threads. Iterators on the returned map are weakly consistent,<a name="line.586"></a>
<span class="sourceLineNo">587</span>   * returning elements reflecting the state of the map at some point at or since the creation of<a name="line.587"></a>
<span class="sourceLineNo">588</span>   * the iterator. They do not throw {@link ConcurrentModificationException}, and may proceed<a name="line.588"></a>
<span class="sourceLineNo">589</span>   * concurrently with other operations.<a name="line.589"></a>
<span class="sourceLineNo">590</span>   *<a name="line.590"></a>
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<span class="sourceLineNo">592</span>   * be performed atomically on the returned map. Additionally, {@code size} and {@code<a name="line.592"></a>
<span class="sourceLineNo">593</span>   * containsValue} are implemented as bulk read operations, and thus may fail to observe concurrent<a name="line.593"></a>
<span class="sourceLineNo">594</span>   * writes.<a name="line.594"></a>
<span class="sourceLineNo">595</span>   *<a name="line.595"></a>
<span class="sourceLineNo">596</span>   * @param computingFunction the function used to compute new values<a name="line.596"></a>
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<span class="sourceLineNo">599</span>   *     {@link com.google.common.cache.CacheBuilder}, with {@link #makeComputingMap} being replaced<a name="line.599"></a>
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<span class="sourceLineNo">601</span>   *     &lt;a href="http://code.google.com/p/guava-libraries/wiki/MapMakerMigration"&gt;MapMaker<a name="line.601"></a>
<span class="sourceLineNo">602</span>   *     Migration Guide&lt;/a&gt; for more details.<a name="line.602"></a>
<span class="sourceLineNo">603</span>   *     &lt;b&gt;This method is scheduled for deletion in February 2013.&lt;/b&gt;<a name="line.603"></a>
<span class="sourceLineNo">604</span>   */<a name="line.604"></a>
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<span class="sourceLineNo">606</span>  @Override<a name="line.606"></a>
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<span class="sourceLineNo">615</span>   * Returns a string representation for this MapMaker instance. The exact form of the returned<a name="line.615"></a>
<span class="sourceLineNo">616</span>   * string is not specificed.<a name="line.616"></a>
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<span class="sourceLineNo">653</span>   * resulting in notification could have occured to an entry being manually removed or replaced, or<a name="line.653"></a>
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<span class="sourceLineNo">655</span>   * collection.<a name="line.655"></a>
<span class="sourceLineNo">656</span>   *<a name="line.656"></a>
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<span class="sourceLineNo">658</span>   * Implementations of this interface should avoid performing blocking calls or synchronizing on<a name="line.658"></a>
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<span class="sourceLineNo">660</span>   *<a name="line.660"></a>
<span class="sourceLineNo">661</span>   * @param &lt;K&gt; the most general type of keys this listener can listen for; for<a name="line.661"></a>
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<span class="sourceLineNo">663</span>   * @param &lt;V&gt; the most general type of values this listener can listen for; for<a name="line.663"></a>
<span class="sourceLineNo">664</span>   *     example {@code Object} if any key is acceptable<a name="line.664"></a>
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<span class="sourceLineNo">673</span>  /**<a name="line.673"></a>
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</pre>
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